Both alpha and beta cyanoethylphthalates are known and have provided a useful class of chemical compounds in a variety of applications including plasticizers. These compounds have been prepared by reacting lactonitrile and hydracrylonitrile with phthaloyl halides in the presence of pyridine. Various methods are also known for preparation of these chemical compounds and which have included complicated processing steps when a purified product was desired. Extraction of the contaminant from the reaction mixture was ordinarily employed followed by distillation of the purified mixture to provide the final product.
The particular extraction procedure heretofore employed for alpha-cyanoethylphthalate purification was both lengthy and involved. Individual extraction steps were conducted in packed columns with deionized water, sulfuric acid, potassium carbonate, and saturated salt solutions, with the extraction schedule further involving repetition of earlier employed extraction liquids. The final extract obtained in this manner was an organic liquid solution of purified alpha-cyanoethylphthalate from which by-products and side-reaction products as well as unreacted starting compounds had been removed. The purified product was separated from the extract solution by a two-step method which involved several evaporations of the organic liquid solvent followed by distillation of the stripped mixture in a molecular still.
A simpler purification method for alpha-cyanoethylphthalate preparation to reduce the processing steps as well as the equipment employed would be desirable.